The present invention relates to a system for controlling the clutch current of an electromagnetic clutch disposed between an engine and the transmission of a motor vehicle.
A clutch torque control system for the drive of a vehicle is, for example, disclosed in British Patent GB No. 2071803B. In the system, the clutch current flowing in a coil of the clutch is controlled in accordance with various signals responsive to operations by a driver, to engine speed, and to vehicle speed. The clutch current increases with respect to the increase of the engine speed for starting the vehicle. When vehicle speed reaches a predetermined speed (for example 20 km/h), a rated current flows through the coil, so that the clutch is entirely engaged.
In such a clutch current control system, the control operation at the start of the vehicle is initiated upon conditions that the vehicle is at a stop and an accelerator pedal is depressed. For the detection of the accelerator pedal, an accelerator pedal switch is provided. If the accelerator pedal switch fails to detect the depression of the accelerator pedal or breaks down, the vehicle can not be started.